Present focusing and zooming functions of optical systems involve the mechanical positioning of lens elements relative to each other. This has the disadvantages of mechanical complexity, bulkiness, and, when electrically operated, high power consumption. The trend towards smaller cameras, especially those used in cell phones, has driven the need for smaller, more compact, and power-efficient optical systems. This has spurred the development of lens elements that change focal length without the need for conventional mechanical positioning. One type of such a lens is the electroactive lens, which changes focal length with the application of voltage. In many instances, the electroactive lens responds primarily to the RMS value of the applied signal regardless of wave shape. Electroactive lenses include liquid lenses and liquid crystal lenses.